Strength softening at shear bands in metallic glasses

The plasticity of metallic glasses (MGs) is mediated by localized shearing in thin bands, degrading the mechanical properties at shear bands (SBs), which can cause shear localization and poor deformability. Quantifying the strength loss at SBs in MGs is important for both further material improvement and failure prediction. By applying a combination of microscale bending with in situ tensile tests, we successfully determine the strength loss at SBs in two typical MGs, namely Zr41Ti14Cu12.5Ni10Be22.5 and (Cu50Zr50)95Al5, that are about 20% lower than those of their intact counterparts. We further notice, based on fractographic examinations, that stable SBs may induce only a negligible heat, but unstable SBs give rise to a high temperature increase in SBs. This observation sheds light on the controversy about whether SBs in MGs must be hot.